What absorbs at 1146 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1146 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.

Possible functional-group assignments

Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.

Spectrum logic

This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 1146 cm⁻¹ is usually not enough for material identification by itself.

Real-world usage

This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.

Common mistakes

• Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
• Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
• Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.

Verification advice

When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.

Literature behind these assignments

• Acetate confidence 1.0

  “Similarly a peak at 1146 that 8 corresponds to C-O-C stretching was significantly decreased in intensity after microbial”

  Degradation of polyester polyurethane by an indigenously developed consortium of Pseudomonas and Bacillus species isolated from soil DOI: 10.1016/j.polymdegradstab.2016.11.003
• Acetate confidence 1.0

  “cm-1 In the case of pure PEO, for the distinctive peaks between 800-1400 in the spectrum, the cm-1, stretching vibration peak of C-O-C splits into three peaks at 1146, 1110, and 1062 and the two cm-1 bands appeared at 1344, and 1359 can be”

  Preparation and Composition Optimization of PEO:MC Polymer Blend Films to Enhance Electrical Conductivity DOI: 10.3390/polym11050853
• Alkyl C-H confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Novel Hemocompatible Imine Compounds as Alternatives for Antimicrobial Therapy in Pharmaceutical Application DOI: 10.3390/pr8111476
• Carbohydrate confidence 1.0

  “The band at cm-1, 1146 has been linked to polysaccharides in previous studies, specifically to the C-O-C 1146 cm-1, has been linked to polysaccharides in previous studies, specifically to the C-Ostretching of the glycosidic link in the cell”

  Comparison of Spectroscopy-Based Methods and Chemometrics to Confirm Classification of Specialty Coffees DOI: 10.3390/foods11111655
• Amide confidence 1.0

  “cm-1 CC to the stretching of aromatic ring, band at 1444 cm-1 C-N and the band at 1290 to the stretching vibration cm-1 [ν(C-N)].35 The last additional band at 1146 resolved ≥ in the spectra of PANI bases prepared with [BzQ] 0.01 M is not”

  Blaha 等 - 2019 - Role of p-Benzoquinone in the Synthesis of a Condu DOI: 10.1021/acsomega.9b00542
• Acetate confidence 1.0

  “There cm-1 is a distinct band at 1146 due to C-O-C stretching.”

  Hagos 等 - 2022 - NEW ANALYTICAL METHODS FOR THE DETERMINATION OF AS DOI: 10.4314/bcse.v36i2.3
• Acetate confidence 1.0

  “1437cm-1 Strong bands present at 1449 and originate from The suspended gray particles can be precipitated by placing 1146cm-1 the O-CH3 bending vibrations.”

  Hussain 等 - 2017 - Surfactant Incorporated Co Nanoparticles Polymer C DOI: 10.1155/2017/7191590
• Acetate confidence 1.0

  “1237 C-O stretching vibration peak in amides w 1146 C-O-C antisymmetric stretching vibration w”

  The analysis and identification of charred suspected tea remains unearthed from Warring State Period Tomb DOI: 10.1038/s41598-021-95393-w